Emulation of Synchronous Generator for Frequency Control of Smart Microgrids Frack Auger, Pablo Federico; Martinez, Maximiliano; Molina, Marcelo Gustavo; Mercado, Pedro Enrique Microgrids (MGs) are emerging as a new paradigm for the integration of Distributed Generation (DG) assets. These novel grid structures present significant benefits to the Electric Power System. One of the most important benefits is the reliability improvement due to the capacity of islanded standalone operation. Nevertheless, this stand-alone operation can bring some problems related to frequency control, especially in MGs with many DG units connected through power electronics interfaces. In this case, the frequency control capacity and hence the stability margins are drastically reduced. This paper presents the design and implementation of a proton exchange membrane fuel cell integrated with supercapacitor energy storage and its control strategy for the frequency control of ac-MGs.

El ocaso del positivismo jurídico incluyente; The decline of Inclusive Legal Positivism Etcheverry, Juan Bautista Este trabajo busca dilucidar si el positivismo incluyente logra renovar la tradición del positivismo jurídico o si, por el contrario, es un reflejo de su decadencia. Para ello, en primer lugar, se presentarán las principales tesis del positivismo incluyente y se advertirá cómo redefine algunas de las tesis tradicionales del positivismo jurídico. Luego se pondrá de manifiesto en qué medida dicha redefinición supone una renovación o un abandono de la tradición positivista. A partir de estos desarrollos se mostrarán las dificultades que tiene el positivismo incluyente para explicar la objetividad de los criterios morales que son incorporados en los sistemas jurídicos actuales. Dichas dificultades de algún modo también afectan su concepción de la discrecionalidad judicial. Además, se sostendrá que esta versión del positivismo jurídico tampoco puede ser presentada (como pretendieron algunos de sus defensores) como una alternativa eficaz frente a la arbitrariedad legal. Por último, se afirmará que el tipo de approach avalorativo del positivismo incluyente lo conduce a resultados poco relevantes.; The purpose of this work is to elucidate if inclusive legal positivism can renovate legal positivism´s tradition or if it is a reflection of its decadence. To that end, the main thesis of inclusive legal positivism will be explained and it will be showed how they redefine some of traditional positivism’s thesis. Next, it will be explained in which way this redefinition of traditional thesis update or leave legal positivism tradition. On this basis, it will be proposed that inclusive positivism has difficulties to explain the objectivity of the moral principles and standards that are incorporated in current legal systems. These difficulties also affect inclusive positivism´s conception of judicial discretion. It will be also held that this version of legal positivism cannot be presented as an effective alternative against legal arbitrariness. Finally, it will be claimed that the non-evaluative approach of inclusive positivism lead to non-interesting or irrelevant outcomes.

Tsallis’ maximum entropy ansatz leading to exact analytical time dependent wave packet solutions of a nonlinear Schrödinger equation Curilef, S.; Plastino, Ángel Ricardo; Plastino, Ángel Luis Tsallis maximum entropy distributions provide useful tools for the study of a wide range of scenarios in mathematics, physics, and other fields. Here we apply a Tsallis maximum entropy ansatz, the q-Gaussian, to obtain time dependent wave-packet solutions to a nonlinear Schrödinger equation recently advanced by Nobre, Rego-Monteiro and Tsallis (NRT) [F.D. Nobre, M.A. Rego-Monteiro, C. Tsallis, Phys. Rev. Lett. 106 (2011) 140601]. The NRT nonlinear equation admits plane wave-like solutions (q-plane waves) compatible with the celebrated de Broglie relations connecting wave number and frequency, respectively, with energy and momentum. The NRT equation, inspired in the q-generalized thermostatistical formalism, is characterized by a parameter q and in the limit q→1 reduces to the standard, linear Schrödinger equation. The q-Gaussian solutions to the NRT equation investigated here admit as a particular instance the previously known q-plane wave solutions. The present work thus extends the range of possible processes yielded by the NRT dynamics that admit an analytical, exact treatment. In the q→1 limit the q-Gaussian solutions correspond to the Gaussian wave packet solutions to the free particle linear Schrödinger equation. In the present work we also show that there are other families of nonlinear Schrödinger-like equations, besides the NRT one, exhibiting a dynamics compatible with the de Broglie relations. Remarkably, however, the existence of time dependent Gaussian-like wave packet solutions is a unique feature of the NRT equation not shared by the aforementioned, more general, families of nonlinear evolution equations.

On the enigmatic Heterostomus curvipalpis Bigot, 1857, with a description of the pupa (Diptera, Brachycera) Coscarón, Sixto; Coscarón, María del Carmen; Gil Azevedo, Leonardo H. The previously unknown pupa of Heterostomus curvipalpis Bigot is described. The morphology of the pupa of Heterostomus is compared with the pupae of Xylophagomorpha, Tabanomorpha and Stratiomyomorpha families, based on five characters, and its phylogenetic position is discussed. Currently placed in Xylophagidae, we conclude that the pupa of Heterostomus shares most characters with the pupae of Pelecorhynchidae.

Tomato second cycle hybrids differ from parents at three levels of genetic variation Liberatti, David Rodolfo; Rodríguez, Gustavo Rubén; Zorzoli, Roxana; Pratta, Guillermo Raúl

Investigation of residual hepatitis C virus in presumed recovered subjects Fujiwara, Kei; Allison, Robert. D.; Wang, Richard Y.; Baré, Patricia; Matsuura, Kentaro; Schechterly, Cathy; Murthy, Krishna; Marincola, Francesco M.; Alter, Harvey J. Recent studies have found hepatitis C virus (HCV) RNA in peripheral blood mononuclear cells (PBMCs) of the majority of presumed recovered subjects. We investigated this unexpected finding using samples from patients whose HCV RNA and anti-HCV status had been serially confirmed. HCV RNA was detected in PBMCs from 66/67 chronic HCV carriers. Subpopulation analysis revealed that the viral load (log copies/10(6) cells) in B cells (4.14 ± 0.71) was higher than in total PBMCs (3.62 ± 0.71, p<0.05), T cells (1.67 ± 0.88, p<0.05), and non-B/T cells (2.48 ± 1.15, p<0.05). HCV negative-strand RNA was not detected in PBMCs from any of 25 chronically infected patients. No residual viral RNA was detected in total PBMCs or plasma of 59 presumed recovered subjects (11 spontaneous, 48 treatment-induced) using nested real-time PCR with a detection limit of 2 copies/µg RNA (from ∼1x10(6) cells). PBMCs from two healthy HCV-negative blood donors became HCV RNA positive, with B-cell predominance, when mixed in vitro with HCV RNA positive plasma, thus passively mimicking cells from chronic HCV carriers. No residual HCV was detected in liver or other tissues from two spontaneously recovered chimpanzees. Conclusion: 1) HCV RNA was detected in PBMCs of most chronic HCV carriers and was predominant in the B cell subpopulation; 2) HCV detected in PBMCs was in a non-replicative form; 3) HCV passively adsorbed to PBMCs of healthy controls in vitro becoming indistinguishable from PBMCs of chronic HCV carriers; 4) Residual HCV was not detected in the plasma or PBMCs of any spontaneous or treatment recovered subjects or in chimpanzee liver suggesting that the classic pattern of recovery from HCV infection is generally equivalent to viral eradication.

Allele identification for transcriptome-based population genomics in the invasive plant Centaurea solstitialis Dlugosch, Katrina M.; Lai, Zhao; Bonin, Auélie; Hierro, Jose Luis; Rieseberg, Loren H. Transcriptome sequences are becoming more broadly available for multiple individuals of the same species, providing opportunities to derive population genomic information from these datasets. Using the 454 Life Science Genome Sequencer FLX and FLX-Titanium next-generation platforms, we generated 11−430 Mbp of sequence for normalized cDNA for 40 wild genotypes of the invasive plant Centaurea solstitialis, yellow starthistle, from across its worldwide distribution. We examined the impact of sequencing effort on transcriptome recovery and overlap among individuals. To do this, we developed two novel publicly available software pipelines: SnoWhite for read cleaning before assembly, and AllelePipe for clustering of loci and allele identification in assembled datasets with or without a reference genome. AllelePipe is designed specifically for cases in which read depth information is not appropriate or available to assist with disentangling closely related paralogs from allelic variation, as in transcriptome or previously assembled libraries. We find that modest applications of sequencing effort recover most of the novel sequences present in the transcriptome of this species, including single-copy loci and a representative distribution of functional groups. In contrast, the coverage of variable sites, observation of heterozygosity, and overlap among different libraries are all highly dependent on sequencing effort. Nevertheless, the information gained from overlapping regions was informative regarding coarse population structure and variation across our small number of population samples, providing the first genetic evidence in support of hypothesized invasion scenarios.

Spin-spin correlations between two Kondo impurities coupled to an open Hubbard chain Tiegel, A. C.; Dargel, P. E.; Hallberg, Karen Astrid; Frahm, H.; Pruschke, T. In order to study the interplay between Kondo and Ruderman-Kittel-Kasuya-Yosida interaction, we calculate the spin-spin correlation functions between two Kondo impurities coupled to different sites of a half-filled open Hubbard chain. Using the density-matrix renormalization group (DMRG), we reexamine the exponents for the power-law decay of the correlation function between the two impurity spins as a function of the antiferromagnetic coupling J , the Hubbard interaction U , and the distance R between the impurities. The exponents for finite systems obtained in this work deviate from previously published DMRG calculations. We furthermore show that the long-distance behavior of the exponents is the same for impurities coupled to the bulk or to both ends of the chain. We note that a universal exponent for the asymptotic behavior can not be extracted from these finite-size systems with open boundary conditions.

Perfil nutricional y dializabilidad de minerales de alimentos de interés social Galan, Maria Gimena; González, Rolando J.; Drago, Silvina Rosa Introducción: evaluar la composición, digestibilidad proteica (DP) y bioaccesibilidad de Fe, Zn y Ca (antes y luego de la cocción) de Alimentos de Interés Social (AIS). Material y Métodos: se analizaron 4 AIS. La composición se determinó según AOAC (2000). La bioaccesibilidad de minerales se estimó a través del porcentaje del mineral dializado, luego de un proceso de digestión que simula los procesos gastrointestinales. El aporte potencial (AP) de minerales se estableció como el producto de su concentración y dializabilidad. La DP se determinó por digestión enzimática y midiendo el incremento del nitrógeno no proteico. Resultados: la composición de AIS fue la siguiente: proteínas: 11,53-24,67g/100g; grasa: 4,31–8,46g/100g; cenizas: 2,95–3,66g/100g; fibra dietaria: 0,6–4g/100g; carbohidratos: 49,38–60,37g/100g; energía: 366,05–389,38Kcal/100g; Fe: 28,91-60,41mg/Kg; Zn: 5,99–33,08mg/Kg; Ca: 1127,69-417,39mg/Kg; Na: 2517,21–13217,50mg/Kg. La DP estuvo en un rango de 58–92%. Los alimentos cocidos presentaron una bioaccesibilidad de Fe y Zn menor que los alimentos crudos, lo cual puede atribuirse, en el caso del Fe, a la pérdida de ácido ascórbico que se produce durante la cocción, y para el Zn a interacciones con oros componentes de la matriz alimentaria que dificultan su liberación durante los procesos digestivos. Según su AP, los AIS cubrirían entre un 10–26% los requerimientos de Fe, 6-8% de los requerimientos de Ca y 2–34% de los requerimientos de Zn. Conclusiones: los AIS, poseen un buen balance nutricional. La disponibilidad de minerales de los AIS fue muy buena y se redujo ligeramente al ser cocidos; Introduction: the aims were to assess the composition, protein digestibility (PD) and bioaccesibility of Fe, Zn and Ca (before and after cooking) of Social Foods (SF). Material and Methods: four SF were analyzed. The composition was determined according to AOAC (2000). Mineral bioaccesibility was estimated by the percentage of dialysated mineral after a digestion process that simulates gastrointestinal processes. Potential contribution (PC) of each mineral was established as the product of its concentration and dialyzability. The PD was determined by enzymatic digestion by measuring the increase of non-protein nitrogen. Results: the SF composition was as follows: proteins: 11.53-24.67g/100g; fat: 4.31-8.46g/100g; ash: 2.95-3.66g/100g; dietary fiber: 0.6-4g/100g; carbohydrates: 49.38-60.37g/100g; energy: 366.05-389.38Kcal/100g; Fe: 28.91-60.41mg/kg; Zn: 5.99-33.08mg/Kg; Ca: 1127.69-417.39mg/kg; Na: 2517.21-13217.50mg/Kg. The PD ranged from 58 to 92%. Cooked foods presented a Fe and Zn bioaccesibility lesser than raw foods, which can be attributed in the case of Fe to the loss of ascorbic acid occurring during cooking process, and for Zn to the interaction of Zn with food matrix components that hinder its release during the digestive process. According to PC, the FSI cover between 10-26%, 6-8% and 2-34% of Fe, Ca and Zn requirements, respectively. Conclusions: Social Foods have a good nutritional balance. Mineral bioaccesibility was very good and was reduced slightly by cooking.

Immunopathology of Brucella infection Baldi, Pablo Cesar; Giambartolomei, Guillermo Hernan In spite of the protean nature of the disease, inflammation is a hallmark of brucellosis and affected tissues usually exhibit inflammatory infiltrates. As Brucella lacks exotoxins, exoproteases or cytolysins, pathological findings in brucellosis probably arise from inflammation-driven processes. The cellular and molecular bases of immunopathological phenomena probably involved in Brucella pathogenesis have been unraveled in the last few years. Brucella-infected osteoblasts, either alone or in synergy with infected macrophages, produce cytokines, chemokines and matrixmetalloproteinases (MMPs), and similar phenomena are mounted by fibroblast-like synoviocytes. The released cytokines promote the secretion of MMPs and induce osteoclastogenesis. Altogether, these phenomena may contribute to the bone loss and cartilage degradation usually observed in brucellar arthritis and osteomyelitis. Proinflammatory cytokines may be also involved in the pathogenesis of neurobrucellosis. B. abortus and its lipoproteins elicit an inflammatory response in the CNS of mice, leading to astrogliosis, a characteristic feature of neurobrucellosis. Heat-killed bacteria (HKBA) and the L-Omp19 lipoprotein elicit astrocyte apoptosis and proliferation (two features of astrogliosis), and apoptosis depends on TNF-α signaling. Brucella also infects and replicates in human endothelial cells, inducing the production of chemokines and IL-6, and an increased expression of adhesion molecules. The sustained inflammatory process derived from the longlasting infection of the endothelium may be important for the development of endocarditis. Therefore, while Brucella induces a low grade inflammation as compared to other pathogens, its prolonged intracellular persistence in infected tissues supports a long-lasting inflammatory response that mediates different pathways of tissue damage. In this context, approaches to avoid the invasion of host cells or limit the intracellular survival of the bacterium may be suitable to prevent the pathological consequences of Brucella infections. The article presents some of the recent patents related to such approaches.

Controlled adhesion and proliferation of a human osteoblastic cell line by tuning the nanoporosity of titania and silica coatings Bellino, Martin Gonzalo; Golbert, Sebastian; de Marzi, Mauricio Cesar; Soler Illia, Galo Juan de Avila Arturo; Desimone, Martín Federico The engineering of surfaces to control cell adhesion represents an active area of biomaterials research. Herein, we demonstrate that it is possible to tune the adhesion and proliferation of a human osteoblastic cell line (Saos-2) by tailoring the nanopore size of an oxide film coating.

Synthesis and Crystallographic Studies of Disubstituted Carboranyl Alcohol Derivatives: Prevailing Chiral Recognition? Di Salvo, Florencia; Paterakis, Christos ; Ying Tsang, Min ; García, Yolanda; Viñas, Clara ; Teixidor, Francesc ; Giner Planas, José ; Light, Mark E. ; Hursthouse, Michael B. ; Choquesillo Lazarte, Duane The syntheses of new o-carboranyldiols bearing aromatic rings bis-[R(hydroxy)methyl]-1,2-dicarba-closo-dodecaborane (R = 2-pyridyl 1a, 3-pyridyl 1b, 4-pyridyl 1c, 2-quinolyl 1d, 4-quinolyl 1e, henyl 1f) are reported. The compounds are obtained as mixtures of meso (syn) and racemic (anti) stereoisomers with a slight diastereomeric excess (syn:anti ratio of 0.7:1) in all cases but in 1b. The cristal structures of the meso compounds syn-1a.2MeOH, syn-1b, syn-1f.0.25H2 O and racemic anti-1a.MeOH, anti-1a.EtOH, and anti-1d.2H2 O are reported. We provide an analysis of these compounds by means of NMR and X-ray crystallography, in the context of crystal engineering and chiral recognition. The results show that the cristal packings for these alcohols are dominated by the supramolecular O-H...N and/or O-H...O hydrogen bonds. Supramolecular analysis of all compounds in this work reveals that homochiral self-assembly, that is, formation of homochiral hydrogen bonded complexes, prevails over heterochiral self-assembly (formation of heterochiral hydrogen bonded complexes).

Insights into the natural history of Ampullariids from the Lower Río de la Plata Basin, Argentina Martín, Pablo Rafael; Burela, Silvana; Tiecher, María José Apple snails (Ampullariidae) are renowned globally as successful invaders, as voracious pests of aquatic crops and as promoters of ecosystem changes in natural wetlands.

Particle Swarm Algorithms to solve engineering problems: a comparison of performance Tomassetti, Giordano; Cagnina, Leticia Cecilia In many disciplines, the use of evolutionary algorithms to perform optimizations is limited because of the extensive number of objective evaluations required. In fact, in real-world problems, each objective evaluation is frequently obtained by time-expensive numerical calculations. On the other hand, gradient-based algorithms are able to identify optima with a reduced number of objective evaluations, but they have limited exploration capabilities of the search domain and some restrictions when dealing with noncontinuous functions. In this paper, two PSO-based algorithms are compared to evaluate their pros and cons with respect to the effort required to find acceptable solutions. The algorithms implement two different methodologies to solve widely used engineering benchmark problems. Comparison is made both in terms of fixed iterations tests to judge the solution quality reached and fixed threshold to evaluate how quickly each algorithm reaches near-optimal solutions. The results indicate that one PSO algorithm achieves better solutions than the other one in fixed iterations tests, and the latter achieves acceptable results in less-function evaluations with respect to the first PSO in the case of fixed threshold tests.

¿Dónde está el Estado en las reformas educativas del silgo XXI? Suasnábar, Juan Manuel del Valle El artículo presente, sobre la base de los resultados parciales de una investigación en curso, busca aportar elementos para la caracterización de las modificaciones, los cambios y las transformaciones que, en las reformas educativas recientes (2004-2006), han afectado al Estado, analizando dónde está el Estado ?qué capacidades, funciones y significados en relación con la educación escolar, adopta/le son adjudicados- en las reformas educativas del siglo XXI, y ello desde la perspectiva de la gobernabilidad en un doble sentido: como distribución territorial de la capacidad de gobierno (toma de decisiones vinculantes, soberanas y colectivizadas), es decir, como definición de estructuras de gobierno; y, por otro lado, como proceso de legitimación, de elaboración de prácticas articulatorias tendientes a otorgar un sentido hegemónico.

La demostración de la existencia del límite de funciones: análisis de su estudio en la Universidad Otero, Maria Rita; Corica, Ana Rosa En este trabajo presentamos resultados parciales de un estudio realizado en un curso universitario de matemática. Desde la Teoría Antropológica de lo Didáctico se analizó cómo se gestiona el estudio de tareas relativas a demostrar la existencia del límite de funciones de variable real. Dicha tarea cobra un lugar vital en la organización que se termina por estudiar, pues permite entrar en el estudio de otras organizaciones matemáticas que se proponen en el curso. Los principales resultados indican que hay una pérdida de sentido del estudio de la tarea. Las técnicas empleadas por los profesores contribuyen a la reducción del cálculo al álgebra. Si bien, el cálculo se apoya en nociones de álgebra, se trata de un campo donde se necesita una ruptura con ciertas prácticas algebraicas para acceder a él.

Differences in access inhibitory function in children age 9 to 11 years: construct validity of a computerized task Introzzi, Isabel Maria; Richard's, Maria Marta; Aydmune, Yésica According to the tripartite model of inhibition (Hasher et al., 1999; Hasher et al., 2007) the access function is the mechanism that is activated during the initial stages of processing and whose primary function is to limit or prevent the entry of irrelevant information to attentional focus. This mechanism is strongly implicated in selective attention (Bjorklund & Harnishfeger, 1990 Dempster, 1995; Harnishfeger & Bjorklund, 1993; Lane & Pearson, 1982; Lorsbach & Reimer 1997; Müller, Zelazo, Hood, Leone & Rohre, 2004), why evaluation is essential in children. For this, we designed a computerized task based paradigm and experimental Gelade & Treisman (1980) to measure the efficiency in the operation of such inhibition. The task is part of the computerized cognitive self-regulation tasks (TAC) which includes a set of tests evaluating various regulatory mechanisms. The main objective of this study is to analyze the construct validity of the experimental task, using as criteria the performance obtained by children of three age groups (9, 10 and 11). It is assumed that the scores for the different performance indicators should reflect differences in function of the age of the participants, as the inhibition efficiency increases with age. To meet this objective was evaluated (so far) a sample of 74 children aged between 9 and 11 years, of both sexes, students of a privately managed school in Mar del Plata city. In this task the child must point as fast as they can and trying not to make mistakes, the presence or absence of a blue box (white or target stimulus) presented mixed among a set of distractors (blue circles and red squares). The child must press two different keys (Z and M) depending on the presence or absence of the stimulus. Four conditions differ depending on the number of distractors (4, 8, 16 and 32), in every trial half of the distractors are blue circles and the other half are red squares. The higher the response times and the percentage of errors, the lower the efficiency of the access function (Darowski, Helder, Zacks, Hasher & Hambrick, 2008). The task consists of a block of 10 trials practice, followed by three blocks of 40 trials each. The average execution time is 3.12 minutes (SD = 0.45). The results show that with increasing age children also show an increase in the percentage of correct answers (accuracy rate performance) and decreased response times, in all conditions (4, 8, 16 and 32 distractors). It can be inferred that the task program TAC presents solid signs of construct validity as the performance increases with the age of children, confirming the hypothesis which states that the inhibition efficiency is increased as a result of development factor.Keywords: access inhibitory function; computerized tasks; children; construct validity.

Habilidades argumentativas de niños de cuatro años: un análisis de las disputas en situaciones de juego en hogares de niños de población urbano marginada y sectores medios Migdalek, Maia Julieta; Arrue, Josefina Elena Desde una perspectiva psicolingüística y sociocultural del desarrollo humano (Vigotsky, 1964; Nelson, 1996; Werstch, 1998), el objetivo del presente trabajo es presentar un sistema de categorías sobre las habilidades argumentativas de niños pequeños de población urbano marginada y sectores medios, en el marco de disputas en situaciones de juego en el hogar. Numerosas investigaciones se focalizaron en la relación entre lenguaje y juego dramático, principalmente en la adquisición del discurso narrativo y de formas explícitas y descontextualizadas de lenguaje (Seidman, Nelson y Gruendel, 1986; Nelson, 1996; Pellegrini 1984, 1985, 1986; Rosemberg, 2008). Pocos estudios abordaron las características de la argumentación en niños pequeños, dado que se la considera una habilidad discursiva de adquisición tardía (Silvestri, 2001). Sin embargo, desde los dos años de edad es posible identificar enunciados con funciones argumentativas, denominados protoargumentaciones (Silvestri, 2001; Peronard, 1992). En tanto la ampliación de las habilidades argumentativas del niño depende de si el entorno directo e indirecto del niño lo propicie (Silvestri, 2001; Faigembaun, 2012), resulta importante conocer las características de este desarrollo para poder diseñar estrategias educativas que lo promuevan. El corpus está conformado por observaciones de 12 horas de situaciones de la vida cotidiana en el hogar audiograbadas, de 40 niños de cuatro años de edad. Empleando un procedimiento cualitativo (Strauss y Corbin, 1991), se identificaron todas las situaciones de juego y se analizaron las interacciones en el marco de disputas para identificar las estrategias argumentativas a través de las cuales los niños sostienen sus posiciones. Luego se diseñó un sistema de categorías construidas inductivamente: los niños sostienen su posición y persuaden a sus compañeros de juego de realizar determinadas acciones a partir de estrategias verbales de reiteración, anticipación, generalización, mostración, mitigación, descripción y agresión verbal, combinadas con estrategias no verbales que incluyen gestos, gritos y llantos.

Genome sequence analysis of arsenic detoxification and metabolism systems from haloarchaea isolated from high altitude andean lakes (haal) Maldonado, Marcos Javier; Kurth, Daniel German; Ordoñez, Omar Federico; Turjanski, Adrian; Vázquez, Martin; Farias, Maria Eugenia HAAL are distributed across the Puna at altitudes from 4,200 to 6,000 masl. These ecosystems present extreme environmental conditions such as high levels of UV radiation, very high salt concentration (up to 4 Mor 25%), low oxygen tension, large daily temperature fluctuations ranging from 20° C during day to -40° C at night, low nutrient concentrations and the presence of heavy metals and metalloids, mainly arsenic. Among these explored lakes Antofalla and Diamante are considered the most extreme, because of the altitude and its elevated arsenic content (230 mg l-1 in Diamante; 23,000 times higher than the level regarded as safe for drinking water by the World Health Organization). Many prokaryotes, including archaea, are capable of transforming the oxidation or reduction state of metals and have the ability to derive energy in processes leading to either their solubilization or biomineralization. Arsenic is one of the most toxic environmental factors in these environments. Archaea carry genes for arsenic resistance, detoxification and metabolism. The most common system is the ars operon(arsRBCAD) composed by the ATPase (ArsA), arsenate reductase(ArsC) and an efflux pump (ArsB). Another less known system is the arsenite transporter ACR3. Other systems related to energy production from arsenic are the arr genes for the arsenate reductase that functions in anaerobic respiration, and the aso (aro,aox) genes for the arsenite oxidase that functions in aerobic resistance to arsenite.The aim of this study was to elucidate and test the genetic mechanisms of tolerance to high arsenic concentrations, taking advantage of the available genome of a strain isolated from HAAL. We studied the strains Halorubrum sp. AJ67 and Halorubrum sp. AD156, isolated from Antofalla and Diamante lakes respectively. The effect of As[V] and As[III] during growth in rich media was evaluated by different protocols. The presence of the aso, ACR3 and arr genes was assessed by degenerate oligonucleotides. PSI-BLAST and ClustalW were used to compare and align sequences, and phylogenetic trees were built using Mega5. Genome sequences were obtained using a whole-genome shotgun strategy with a 454 GS Titanium pyrosequencer at INDEAR, Argentina. Genomes were annotated and analyzed in the RAST annotation server. These isolates show enhanced resistance compared to other archaea carrying the ars operon. This could be explained by the presence of additional genes related to this function, including extra copies of the ars operon or supplementary extrusion pumps. These results suggests that the acr3, arr and aso genes in general may be more important than previously thought in environmental arsenic cycling and mobilization. Organisms with high tolerance to As, isolated in pure culture from these environments, are candidates for studies of bioremediation of metals and metalloids, a methodology of low cost and environmentally friendly.

Pólen nas Angiospermas: diversidade e evolução Girardi Bauermann, Soraia; Nunes Radaeski, Jefferson; Cardoso Pacheco Evalt, Andreia; Pereira Queiroz, Elisa; Mourelle Civano, Dominique; Prieto, Aldo Raul; da Silva, Claudia Inés Ao reunir as coleções de referência de seus diversos autores, esta obra tem por objetivo oferecer ao leitor uma ampla visão das diferentes morfologias polínicas registradas nos laboratórios de palinologia envolvidos no projeto. Para facilitar a utilização do livro, juntamente com as descrições polínicas se apresenta a distribuição fitogeográfica de cada táxon estudado. A adição da ocorrência dos táxons, juntamente com as descrições, faz com que essa flora polínica seja de especial interesse por sua aplicação nos trabalhos de reconstituição vegetacional.